Cool-weather flowers decline quickly once temperatures reach 80 degrees during the day. Snapdragons are especially sensitive to heat and contract rust disease. When you see yellow spots on the top of the leaf and rust spores on the underside, pull the plants and dispose of them in the compost pile.

Zinnias are a great choice to replace snapdragons. There are many selections that can be planted by seed.

My favorite transplant is Dreamland. It has large rounded flowers in yellow, pink, red, lavender and white. The plants grow to about 20 inches tall.

Other transplants include the tough Profusion zinnias, available in yellow and pink, and Lilliputs.

Zinnias require full sun, and they work well in containers. Hummingbirds and butterflies are attracted to them.

Zinnias tolerate extreme heat, but they are not xeriscape plants. Watering twice a week is the usual requirement.

In some neighborhoods, deer do not eat zinnias. Spray some test plantings with Liquid Fence once a week for three weeks to allow the plants to become established before the deer check them out.

Calvin R. Finch is a horticulturist and director of the Texas A&M Water Conservation and Technology Center. Contact him at calvin.finch@tamu.edu.